Six protocols are currently active and conducted out of the Consultation- Liaison Service-based behavioral medicine research program. These protocols examine the phenomenology and biological correlates of illness or treatment-induced mood, behavioral, and cognitive changes. The protocols address such areas as: a) the psychiatric phenomenology of certain diseases and their treatment; b) the treatment response characteristics of psychiatric disorders associated with medical diseases or their treatment; c) biochemical factors that may serve as predictive diagnostic markers for illness or for treatment-associated mood/behavioral or cognitive syndromes; d) the effects of mood state alterations on immunologic function. Significant findings to date include demonstration of the following: 1) additional and more robust evidence of conditioned immunostimulation; 2) increased MRS determined brain magnesium in 13 patients with major depression compared with 22 normal volunteers and 21 alcoholics; 3) a significant inverse relationship between skeletal magnesium and serum total magnesium in 60 normal volunteers; 4) markedly different concentrations of free magnesium in different tissues; 5) evidence for a serotonin reuptake inhibitor withdrawal-induced mania in patients with stuttering as well as pimozide- induced psychosis in the same patient group.